In many commercial applications, it is desirable to promote the dissolution of gas into liquid. Examples of such applications include fish farming, beverage manufacture, and wastewater treatment. In general, one technique for promoting dissolution of gas into liquid involves sparging the gas in the liquid, that is, passing the gas through a device that emits the gas in small bubbles into the liquid. Some techniques employ venturi-type devices wherein the liquid is impelled through a device having a converging-diverging cross-section to increase the liquid velocity and turbulence intensity, wherein the gas stream is fed into the liquid as it passes through the device.
Surface tension between the gas and liquid can inhibit the injected gas stream from dispersing into bubbles. Energy in the form of kinetic energy, potential energy or turbulent mixing must be applied to the gas and/or liquid stream to overcome surface tension and disperse the gas stream or large bubbles into smaller bubbles. While large bubbles are easy to break, the surface area to volume ratio is in an inverse relationship with the bubble radius. Increasing energy intensity is required to overcome surface tension of the larger bubbles to form finer bubbles. Therefore, these conventional techniques require significant energy and turbulent intensity to generate finer gas bubbles.
The known techniques encounter pressure drops and other operational constraints that require high energy input, without necessarily producing satisfactory results. The present invention provides improved results in dissolution while requiring much less energy.